3-Dimensional Voronoi Mesh
TL;DR: use wireframe modifier and a subdivision modifier.
Blender 2.9 instructions
Step 1: particle system


Step 2: Cell fracture
Enable the add-on cell fracture

Hit okay

Step 3: Joining
select new pieces

Join

In edit mode, merge nearby verts:

Step 4: Wireframe
Add wireframe modifier (disable Even Thickness)

Add remesh modifier with voxels in order to repair broken geometry from wireframe modifier

Step 5: smoothen
Add decimate modifier to simplify geometry

Add subdivision modifier to smooth the surface